Colchicine and related alkaloids, such as merenderine, colchamine, β and γ-lumicolchicine, 2-demethyl colchicine, jolantamine, cornigenine were isolated from various Merendera species. In a previous study by us, some polypeptides and amino acids with antitumour activity (169% activity at 400 mg/kg dose in 3PS test system) were isolated from Merendera caucasica. The aqueous alcoholic extract of the plant, when acidified with sulphuric acid and extracted with chloroform, yielded a crude alkaloidal mixture which showed high antitumour activity (220% at 22 mg/kg dose; 190% at 14 mg/kg dose in 3PS test system). The crude alkaloidal mixture was separated by preparative TLC using CHCl3:EtOH (9:1) as developing solvent, yielding the following alkaloids: γ-Lumicolchicine (43 mg, 17% activity at 50 mg/kg dose), colchicine (150 mg, 265% activity at 12.5 mg/kg dose), N-formyl deacetyl colchicine (5 mg), and demethyl colchicine (17% activity at 50 mg/kg dose when combined with N-formyl deacetyl colchicine).